Type 1 diabetes (T1D) is a chronic autoimmune disease with high risk for long-term morbidity and mortality. Although insulin can provide a relatively normal life for the affected children and adults, the therapy poses risk for seizures, coma, and death and even compliant patients are not always protected from complications such as blindness, renal failure, and amputation. Our current understanding of the disease paints a complex picture in which nearly every immune cell is involved. These interactions include requisite contributions from T cells, B lymphocytes, dendritic cells, and macrophages. The activation of these cells results in a state of tissue inflammation and ultimate destruction of insulin-producing islet beta cells by proinflammatory cytokines and other noxious products of inflammation. To activate the transcriptional program associated with the inflammatory state, these deleterious signals must be transduced from the cell surface to the nucleus. This process requires the nuclear import of proinflammatory transcription factors and depends on the action of karyopherin/importin complexes. We have developed a cell-penetrating inhibitor of nuclear import which suppresses accelerated diabetes and insulitis for one year in NOD mice, the most widely used model of human disease. In this proposal, we will test the central hypothesis that targeting two key control points required for the inflammatory response will ameliorate and possibly reverse autoimmune diabetes. In aim 1, we will determine the efficacy of a nuclear import inhibitor in preventing or reversing spontaneous diabetes and will elucidate its mechanism of action. A second key step in inflammation is the activation of the mainstays of innate immunity, toll-like receptors (TLRs). These receptors have been implicated in diabetes pathogenesis and their activation can break immune tolerance. Signaling through these receptors depends on two key adaptor proteins, MyD88 and TRIP. In specific aim 2, we will develop cell-penetrating inhibitors of these pathways and test their efficacy in suppressing or reversing Type 1 diabetes. Overall, we will target both the proximal (adaptor protein activation) and distal (nuclear translocation) control points of proinflammatory signaling using innovative cell-penetrating peptides and proteins. Targeting these crucial intracellular signaling events represents a new strategy to ameliorate Type 1 diabetes. PUBLIC HEALTH RELEVANCE: Type 1 diabetes is a chronic illness that begins in childhood and afflicts more than 2 million Americans. Those affected face a life-time of injections without certainty that they will be protected from disease complications. We will test new pathways in T1D development and apply innovative approaches to target these pathways to reveal new strategies for prevention and reversal of this devastating illness.